1. Field of the Invention
The present invention relates to a motion guide apparatus, such as a linear motion guide apparatus or a ball screw device, and more particularly to a motion guide apparatus including two movable members or a screw shaft and a ball nut movable relative to each other, and a deflecting device attached to one of the two movable members for suitably deflecting and guiding the ball bearing elements to move through an endless ball guiding passage in the ball screw device or between the two movable members.
2. Description of the Prior Art
Typical motion guide apparatuses, such as the linear motion guide apparatuses or the ball screw devices comprise two movable members rotatable or movable relative to each other, and a number of ball bearing elements disposed between the two movable members for facilitating the sliding movement between the two movable members, and two or more end deflecting elements attached to the ball nut and communicative with the helical groove portions of the screw shaft and the ball nut for forming an endless ball guiding passage in the ball screw device or between the two movable members and for slidably receiving a number of ball bearing elements.
For example, U.S. Pat. No. 7,350,434 to Nishimura et al; discloses one of the typical ball screw devices comprising a ball nut pivotally or rotatably coupled onto a screw shaft, and a helically running threaded channel provided between the screw shaft and the ball nut for receiving a number of loaded ball bearing elements and for facilitating the sliding movement between the screw shaft and the ball nut, and two or more end deflecting elements attached to the ball nut and communicative with the helical groove portions of the screw shaft and the ball nut for forming the endless helically running threaded channel in the ball screw device or between the screw shaft and the ball nut.
However, the deflecting channels in the deflecting elements include a circular cross section all through the length thereof and may not be suitably aligned with or flush with the helical groove portions or the endless helically running threaded channel of the screw shaft and the ball nut, and such that the loaded ball bearing elements may not be suitably guided to move through the endless helically running threaded channel of the screw shaft and the ball nut.
U.S. Patent Publication No. 2007/0221003 to Chen et al. discloses another typical ball screw device also comprising a ball nut pivotally or rotatably coupled onto a screw shaft, and a helically running threaded channel provided between the screw shaft and the ball nut for receiving a number of loaded ball bearing elements and for facilitating the sliding movement between the screw shaft and the ball nut, and two or more end deflecting elements attached to the ball nut and communicative with the helical groove portions of the screw shaft and the ball nut for forming the endless helically running threaded channel in the ball screw device or between the screw shaft and the ball nut.
However, the deflecting channels in the deflecting elements also include a circular cross section all through the length thereof and may not be suitably aligned with or flush with the helical groove portions or the endless helically running threaded channel of the screw shaft and the ball nut, and such that the loaded ball bearing elements may not be suitably guided to move through the endless helically running threaded channel of the screw shaft and the ball nut.
U.S. Patent Publication No. 2008/0115609 to Tsou et al. discloses a further typical ball screw device also comprising a ball nut pivotally or rotatably coupled onto a screw shaft, and a helically running threaded channel provided between the screw shaft and the ball nut for receiving a number of loaded ball bearing elements and for facilitating the sliding movement between the screw shaft and the ball nut, and two or more end deflecting elements attached to the ball nut and communicative with the helical groove portions of the screw shaft and the ball nut for forming the endless helically running threaded channel in the ball screw device or between the screw shaft and the ball nut.
However, the deflecting channels in the deflecting elements also include a circular cross section all through the length thereof and may not be suitably aligned with or flush with the helical groove portions or the endless helically running threaded channel of the screw shaft and the ball nut, and such that the loaded ball bearing elements may not be suitably guided to move through the endless helically running threaded channel of the screw shaft and the ball nut.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional motion guide apparatuses.